Hereditary and sporadic
cerebellar ataxias represent a vast and still growing group of diseases whose diagnosis and differentiation cannot only rely on clinical evaluation. Brain imaging including magnetic resonance (MR) and nuclear medicine techniques allows for characterization of structural and functional abnormalities underlying symptomatic
ataxias. These methods thus constitute a potential source of radiological
biomarkers, which could be used to identify these diseases and differentiate subgroups of them, and to assess their severity and their evolution. Such
biomarkers mainly comprise qualitative and quantitative data obtained from MR including
proton spectroscopy, diffusion imaging, tractography, voxel-based morphometry, functional imaging during task execution or in a resting state, and from SPETC and PET with several radiotracers. In the current article, we aim to illustrate briefly some applications of these neuroimaging tools to evaluation of
cerebellar disorders such as inherited
cerebellar ataxia, fetal developmental malformations, and immune-mediated
cerebellar diseases and of neurodegenerative or early-developing diseases, such as
dementia and
autism in which cerebellar involvement is an emerging feature. Although these radiological
biomarkers appear promising and helpful to better understand
ataxia-related anatomical and physiological impairments, to date, very few of them have turned out to be specific for a given
ataxia with
atrophy of the cerebellar system being the main and the most usual alteration being observed. Consequently, much remains to be done to establish sensitivity, specificity, and reproducibility of available MR and nuclear medicine features as diagnostic, progression and surrogate
biomarkers in clinical routine.